The inventive concepts described herein relate to a semiconductor device, and more particularly, relate to a nonvolatile memory device including a reference cell and a data management method thereof.
Semiconductor memory devices are divided into voltage memory devices and nonvolatile memory devices. While read and write speeds of the volatile memory device are fast, volatile memory devices lose contents stored therein at power-off. On the other hand, the nonvolatile memory devices retain data stored therein even at power-off. Thus, the nonvolatile memory devices are used to store contents which must be retained regardless of whether a power is supplied.
A demand for high-integration and mass random access memory devices is increasing. A semiconductor memory device used for handheld electronic devices may be a flash memory device. But, there has been researched a random accessible nonvolatile element with an improved performance. For example, there have been researched a ferroelectric RAM (FRAM) using a ferroelectric capacitor, a magnetic RAM (MRAM) using a tunneling magneto-resistive (TRM) film, a phase change memory device using a Chalcogenide alloys, a resistive RAM (RRAM) using a variable resistance material as a data storage medium, etc.
The above-described nonvolatile memories may include a reference cell for discriminating data stored in memory cells. More reference cells may be required for high data integrity. However, an increase in the number of reference cells may hinder implementation of high-integration, light and slim nonvolatile memories. Thus, is provided a technique for providing high data integrity without increasing the number of reference cells.